Method of and apparatus for flowing wells



ATTORN EY Jan. 9, 1940. w. E. NlLEs METHOD 0F AND APPARATUS FOR FLOWINGWELLS Filed June 30, 1938 INVENTOR VVI'/ m E. /V/es 'patetica Jan. 9,1940 PATENT OFFICE METHOD oF AND APPARATUS Fon. FLowiNG WELLS William E.Niles, Kansas City, Mo. Application June 30, 1938, Serial No. 216,728

8 Claims.

the fluid levels in the formation or clogging of the producing sandswith paraflin and asphalt. In some instances the hydrocarbons may becomeor are so viscous that they will not flow through the containing sandsinto the well. In cases where the natural pressures become depleted orare insuflicient to lift the liquid that flows into the well, it isnecessary to provide mechanical means to lift the fluid 'that doescollect in the bottom of the well but due to the extreme depth of thepresent day wells, crooked well holes and various mechanicalimperfections in the pumping apparat-us, pumping` rods, pump valves,etc., such methods are diicult and a constant source of trouble. Evenlthough a well has been successfully pumped there comes a time when thefluid level subsides because of clogging of the formation with paraffinand asphalt with the result that much of the hydrocarbons cannot reachthe pump and the well is abandoned.

It is, therefore, the principal object of the present invention toprovide a method and apparatus for effectively extracting oil fromformations wherein the oil cannot ordinarily be recovered by presentmethods.

Other important objects of the invention are to effect flow of the oilthat is ordinarily too viscous to flow through the producing formation;and to continue iiow of wells after depletion of the natural pressure,thereby avoiding the usual pumping difficulties above noted.

It is also an important objectl of the present invention to keep theformation clean, and free of substances that ordinarily tend to clog theiiow passages of the producing formation.

In accomplishing these and other objects of the invention, I haveprovided an improved apparatus, the preferred form of which isillustrated in the accompanying drawing, wherein:

Fig. 1 is a vertical section through a Well equipped with a well flowingapparatus constructed in accordance with the present inven-4 tion.

Fig. 2 is an enlarged horizontal section through the well on the line2-2 of Fig. 1, particularly (Cl. IBG-21) illustrating support of theelectrical conductors by the well tubing.

Fig. 3 is an enlarged horizontal .cross-section through the heaterwhereby the producing formation is heated to effect suflicientvaporization of the fluid contained in the formation'therebyartificially generating sufficient pressure to effect iioW of the well.

Fig. 4 is a vertical section through the heater.

Fig. 5 is an enlarged detail perspective view lo of the heater showing apart of the heater casing in section.

Referring more in detail to the drawing:

I designates the bore hole of an oil well that is drilled from thesurface of the earth into the oil producing formation 2. The bore holeis cased by the ordinary casing 3 that is supported on theI cap-rock 4above the producing formation, as in conventional practice. Locatedwithin the casing and extending from the top to the bottom of the wellisa tubing 5, through which oil flows to the top of the weil undercontrol of a master valve 6 into a lateral flow line 1 leading to astorage tank, pipe line or other source of disposal.

When a well is first completed the oil will 25 usually iiow through theproducing sand and accumulate within the shot-hole 8 by reason ofdifference in the natural pressure existing in the formation and thespace within the well. The oil will continue to enter the well and thefluid will so rise in the tubing until the iiuid pressure is equivalentto the natural formation pressure. Usually this pressure is sufficientto force the oil to the top of the well and the well will flownaturally, but eventually the formation pressure subs 4sides so that itis necessary to provide mechanical .means in lifting the oil or tosupplement the formation pressure with an artificial pressure medium tocontinue the flow. It has been found that when artificial mediums areinjected into the well m they interfere with the natural flow of oilfrom the formation into the shot-hole of the well. When the fluid islifted by a pump or the like difliculty is encountered because ofbreakage of the rods, leakage of pump valves, crooked Well holes, andmany other reasons. I have, therefore, provided an improved method andapparatus for reestablishing a substantially natural formation pressurewhereby the iiow is continued in substantially the same manner as whenconducted 50 under the natural formation pressures.

In carrying out the invention, I have provided means for heating theproducing formation at a point directly below the cap-rock 4 so that theaccumulated heat travels 'back through the formation and eifectssuiiicient vaporization of the fluids remaining in the upper portionthereof to generate pressure which effects flow of oil downwardlythrough the formation and in the direction of the well hole so that theoil is again co1- lected in the well pocket and caused to rise in thetubing as the pressures reestablished. As the pressure in the formationgradually builds up it soon becomes suflicient to again start flow ofthe well in substantially all essentials the same as when lunder itsoriginal, natural now. I am aware that heaters have been provided tomelt paranin, asphalt and like materials tending to clog the flowchannels in the surfaces of the shot-hole and to keep the screen freefrom such accumulations, but in all instances it has been necessary toequip the well with conventional pumping-apparatus to lift the oil tothe top of the well. I have found that by locating the heater at acertain position in the well relatively to the depth of the formationthe heat therefrom is eective in generating pressure which is sufficientto establish natural flow without the use of mechanically operated pumpsand the like, as now to be described.

Located in the tubing at spaced elevations are check valves 9, eachincluding a coupling I that is inserted between adjacent joints oftubing and have ports II provided with valve yseats I2 that are normallyclosed by gravity operated valves I3. the valves I3 being retained invalving position within cages I4 formed as a part of the coupling andadapted to extend upwardly within the tubing. The tubing is sealed fromthe casing at a point above the cap-rock by means of spaced packers I5and I6 so as to prevent escape of accumulated pressure between thetubing and casing sothat the generated pressure is effective in causingow of oil through the tubing.

Fixed to the lower section of the tubing, at a point directly below thecap-rock, is a heater I1 comprising a cylindrical outer casing I8 ofsuitable diameter to be inserted into the well through the well casingand which is of sufllcient length to house the required size resistanceelement to produce the desired heat. Located within the casing I8 areconcentrically arranged cylindrical partitions I9 and 28, the partitionI9 conforming in diameter to that of the tubing so as to form a flowchannel 2I through which theoil fluid is passed through the heater.'I'he outer partition is spaced from the partition I9 to form an annularinsulating space 22 surrounding the ow channel 2I so that the heatgenerated by theresistance elements is insulated from the well flowmoving through the channel 2I. The insulating space may be exhausted ofair or the space may be filled with .suitable insulating material asdesired. The partition 20 cooperates with the outer wall of the casingto form an annular chamber 23 for accommodatingk the heating element 24.'I'he ends of the casing are closed by heads 25 and 26 having internallythreaded collars 21 and 28 to respectively connect the heater with alower joint of tubing and with the threaded neck 29 of a conventionalscreen 30, such as used in ordinary pumping equipment. The screen 38 mayextend to the bottom of the formation or may be supported at the desiredelevation on a conventional stand of pipe, as in regular practice. It isimportant, however,'that the heater be located above the screenso thatthe pressure is generated above the fiow'passageways to the screen, anda liquid seal is maintained relatively to the interior of the tubing.

aieaoao The heating element may be of any desired form and is suppliedwith a suitable current through conductors 3| and 32 that lead from thetop of the well through a conduit 33. The conduit is supported from thetubing 5 by clamping bands 34 located at spaced intervals along thelength thereof as shown in Fig. 2. The conductors 3| and 32 areconnected with the terminals of a generator 35 that is shown in diagramin Fig. 1 and which is driven by a prime mover such as a motor 36,having its terminals connected by conductors 31 and 38 with servicelines 39 and 40. The field coils 4I of the generator are supplied withan exciting current from any slutable source such as the service lines39 and 48, through conductors 42 and 43, one of the conductors beingconnected with a rheostat 44 for regulating voltage of the currentflowing through the neld coils so that the current output of thegenerator may be regulated to provide the desired voltage to produce theheat required in maintaining iiow from the producing formation withoutoverheating and cracking of theoil.

In operating a well flowing apparatus, as above described, the mastervalve 6 may be initially closed and the current supply established tothe heating elements of the heater. As the heat builds up within theupper portion of the shothole the walls of the pocket are heated tovaporize any vaporizable nuids that are contained in -the upper portionof the producing formation.

The heat gradually accumulates in the formation and is carried byconduction in all radial directions from the well hole to effectvaporization of any volatile fluids remaining in the upper portion ofthe formation until finally the pressure is -suflicient to causemovement of liquid petroleum When suilicient pressure has been built upthe master valve is opened to cause the accumulated oil to be ejectedfrom the tubing through the lateral flow line l. The now will thencontinue as long as the articially generated pressure is suilicient.Escape of the gases through the tubing may, perhaps, cause a drop inpressure and theV flow may stop until sufllcient pressure has againbuilt up. Thus the well may possibly flow in heads, that is periods offlow alternate with brief periods of quiescence while suiilcienthydrocarbons are being vaporized to reestablish the required pressure.The generated gas that does escape moves through the column of oil inthe tubing in the form of bubbles to assist flow of the well liquids.

From the foregoing it is apparent that I have provided an improvedmethod and apparatus for producing and maintaining flow of oilfromaip'roQ-j ducing formation after the natural pressure'fhas subsided.It is also obvious that the heatv being conducted through the upperportion of the formation reduces the viscosity of any hydrocarbonsremaining in the lower level and causes their now in the direction ofthe well hole so that the major portion of the hydrocarbons in theformation are extracted and caused to ow to the top of the well.

What I claim and desire to secure by Letters Patent is:

1. An apparatus for owing wells drilled into a producing formationincluding a tubing in the well extending into said formation, a packerin the well for retaining pressure in said formation, a heater carriedby the tubing in the upper portion of the formation for heating acertain portion of the formation to generate pressure on the petroleumcontained in the lower portion of the formation and to effect flow ofsaid petroleum through the formation and through the tubing to the topof the well, means insulating the heater from the ow moving through saidtubing, check means in the tubing for trapping the flow at selectedpoints in the tubing upon drop of pressure in said formation, and amaster4 valve at the upper end of the tubing for controlling said flowto retain the generated pressure.

2. The method of recovering petroleum by way of a well drilled through acap-rock into a producingformation including vaporizing a portion of thepetroleum contained in the formation directly under said cap-rock byapplication of extraneous heat to establish a high pressure area in theformation, and creating a low pressure area at a selected point in theformation below said high pressure area to cause flow of petroleum fromthe high pressure area to said selected point and to the top of the wellwithout increase in temperature of said petroleum when passing saidheated area.

3. The method of recovering petroleum by way of a well drilled through acap-rock into a producing formation including vaporizing a portion ofthe petroleum contained in the formation under said cap-rock byapplication of extraneous heat to establish a high pressure area in theformation, creating a low pressure area at a selected point in theformation below said high pressure area to cause flow of petroleum fromsaid highpressure area to said selected point and for effecting flow ofthe petroleum from said low pressure area to the top of the wellresponsive to the pressure acting in said high pressure area withoutincrease in temperature of said petroleum when passing said heated area,and trapping iaid flow at a series of points above said torina- 4. Themethod of recovering petroleum from petroleum producing formationsincluding heating a portion of the formation to establish a highpressure area in said formation, creating a low pressure area at aselected point in the formation below the high pressure area to causeflow of petroleum upwardly in saidlow pressure area and through saidheating zone without susbtantial increase in temperature, and releasingpressure from the low pressure area to effect flow of said petroleum andto retain said high pressure.

5. The method of recovering petroleum from petroleum producingformations including heating a portion of the formation to establish ahigh pressure area in said formation, creating a low pressure area at aselected point below the high pressure area to cause flow of petroleumto said low pressure area, releasing pressure from the low pressure areato effect flow of said petroleum upwardly through said heating zonewithout additional increase in temperature, and trapping the flow at aseries of points above said formation.

6. An apparatus for flowing wells drilled into a producing formationincluding a tubing in the well extending into said formation, a packerin said well to retain pressure in said formation, a heater carried bythe tubing in the upper portion of the formation for heating saidportion of the formation to generate pressure on the petroleum containedin the lower portion of the formation and to effect ow of said petroleumthrough the formation and through the tubing to the top of the well, andmeans insulating the heater from the flow moving through said tubing.

7. An apparatus for flowing wells drilled into a producing formationincluding a tubing in the well extending into said formation, a packerin said well to retain pressure in said formation, a

heater carried bythe tubing in the upper portion of the formation forheating said portion of the formation to generate pressure on thepetroleum contained in the lower portion of the formation and to effectflow of said petroleum through the formation and through the tubing tothe top of the well, means insulating the heater from the flow movingthrough said tubing, and check means in the tubing for trapping the flowat selected points in the tubing upon drop of pressure in saidformation.

8. An apparatus for flowing wells drilled into a producing formationincluding a tubing in the well extendingl into said formation, a packerin said well to retain pressure in said formation, a heater carried bythe tubing in the upper portion 0f the formation for heating saidportion of the formation to generate pressure on the petroleum containedin the lower portion of the formation and to eiect iiow of saidpetroleum through the formation and through the tubing to the top of thewell, means insulating the heater from said tubing, means in the tubingfor trapping the flow at selected points in the tubing, and a mastervalve at the upper end of the tubing for controlling said flow to retainsaid generated pressure.

4 WILLIAM E. NILES.

